High Voltage Inverting Charge Pumps Offer Low Input & Output Ripple

MILPITAS, CA – May 9, 2012 – Linear Technology Corporation
announces the LTC3260 and LTC3261 versatile high voltage charge pumps. The
LTC3261 is a high voltage inverting charge pump that can deliver up
to 100mA of output current. The LTC3260 has the same charge pump as
the LTC3261, but also includes both positive and negative LDO
regulators that can source up to 50mA output current each. The
negative LDO post regulator is powered from the inverting charge
pump output. The positive and negative LDO output voltages can be
adjusted down to 1.2V and -1.2V, respectively using external
resistor dividers. Both devices operate over a wide 4.5V to 32V
input voltage range.

The internal charge pump of the LTC3260 and LTC3261 function in
either low quiescent current Burst Mode® operation or low noise
constant frequency mode at up to 88% efficiency. In Burst Mode
operation the charge pump output regulates to –0.94 • VIN. Also, in
Burst Mode operation the LTC3261 draws only 60μA of quiescent
current, while the LTC3260 draws only 100uA with both LDOs enabled.
Constant frequency operation offers low input and output ripple; in
this mode the charge pump produces an output equal to –VIN and
operates at a fixed 500kHz or to a programmed value between 50kHz
to 500kHz using an external resistor. Other IC features include low
external parts count with ceramic capacitor stability, soft-start
circuitry to prevent excessive current flow during start-up, plus
short circuit and thermal protection. The LTC3260 and LTC3261 are
well-suited for a variety of applications such as low noise
bipolar/inverting supplies from a high voltage input,
industrial/instrumentation low noise bias generators, portable
medical equipment and automotive infotainment systems.

The LTC3260 is available in a low-profile (0.75mm) 3mm x 4mm
14-lead DFN package and a 16-lead MSOP package, both with a
backside thermal pad. The LTC3261 is available in a 12-lead MSOP
package with backside thermal pad. For both devices, the E- and
I-grade operating junction temperature is -40°C to +125°C.
1000-piece pricing for the E grade starts at $3.40 each for the
LTC3260 and $2.87 each for the LTC3261. Both devices are available
from stock. For more information, visit www.linear.com/product/LTC3260 and www.linear.com/product/LTC3261.

LTC3260: Dual Supply Inverting
Charge Pump

VIN Range: 4.5V to 32V

Inverting Charge Pump Generates –VIN

Charge Pump Output Current Up to 100mA

Low Noise Negative LDO Post Regulator (ILDO- = 50mA Max)

Low Noise Independent Positive LDO Regulator (ILDO+ = 50mA
Max)

100µA Quiescent Current in Burst Mode® Operation with Both LDO
Regulators On